The Hollywood Strangler – Part 1

The Ventura Freeway, running from Woodland Hills to Pasadena, is the Valley’s main – only, really, since the 118 is so far north – east-west freeway. In typical LA fashion, much of the Valley is car-oriented despite the paucity of freeway capacity: just one east-west freeway for nearly 2 million people. The freeway is the famous 101 from Woodland Hills to the Hollywood Split, and the much less famous 134 from the Hollywood Split to Pasadena.

The Ventura Freeway is newer than some of LA’s first freeways, like the 110, the 10, and the Hollywood Freeway portion of the 101, so it doesn’t suffer from the problem of short interchange spacing. However, it’s old enough to have underpowered freeway-to-freeway interchanges at the 405, the Hollywood Split, and the 5. Let’s take a closer look at these three interchanges, as usual with an eye on rationalizing the freeway facility and improving the local streets in the vicinity. For this post, we’ll look at the Hollywood Split, saving the 405 and the 5 for another day.

Before diving in, let’s think about what makes a good freeway-to-freeway interchange. First, these interchanges have larger ramp volumes than typical interchanges, which makes the weaving conflicts worse. That suggests an increased need to avoid conflicting local ramps (a local on-ramp right before the freeway off-ramp, or a local off-ramp right after the freeway on-ramp). Second, these interchanges take up more space than typical interchanges. Therefore, in order to maintain functionality for local traffic distribution, it often makes sense to have an interchange serving local traffic integrated somehow. This can take the form of half diamonds or a full diamond interchanged arranged so that its ramps don’t cause any weaving conflicts. I like to call this an “inside interchange”. Here’s an example: the 134 and the 2, with inside diamonds on the 134 at Harvey and the 2 at Holly.

Now, we don’t want to go blowing massive holes in North Hollywood to drop in 65 mph ramps and create interchanges like they have in undeveloped parts of Fontana. However, these principles can still help us figure out what will work for these cases. We’ll do our best to keep improvements within available right-of-way, compromising on speed where needed. Alright, on we go.

The Hollywood Split is the somewhat confusing junction of the 101, the 170, and 134 in North Hollywood. The 101 enters from the southeast on the Hollywood Freeway and departs to the west on the Ventura Freeway. The leg to the northwest is the 170, and the leg to the east is the 134, both of which end at the interchange.

Despite being signed as the mainline freeway, the 101 exits on the right and merges on the right going east/south, and exits on the right and merges on the left going north/west. This is contrary to modern design standards, which require that the mainline freeway stay left, with exits and entrances to the right.

On the other hand, the interchange also reflects downtown-oriented design, with the movements to/from downtown emphasized at the expense of other movements. This reflects the thinking of the era, that people would drive to a downtown central business district (CBD) in the morning and out to suburbs in the afternoon. With LA’s polycentric development, downtown is not as dominant as it is in many cities. The Ventura Freeway provides important east-west connectivity to outlying CBDs in Sherman Oaks, Burbank, Glendale, and Pasadena. Thus, if one considers the Ventura Freeway the mainline – an argument for which there is a good case, as we shall see – there are only two through lanes, which is also substandard for this location. The Ventura Freeway through movements stay left at the splits entering the interchange, but merge to the right departing the interchange. This means that depending on which movements dominate, we might make different decisions about what to consider the mainline freeway, and which ramps to reconfigure.

Looking at the freeway-freeway ramp layout, we can see that the northwest and southeast quadrant ramps are missing (north to/from west, south to/from east). Again this was fairly typical for that era of freeway design, but leaving out ramps is frowned up these days as it is confusing for motors and shunts high speed traffic onto local streets. The southeast quadrant ramps are more consequential, because they would connect major nodes (Hollywood to Burbank & Glendale), while the missing northwest quadrant ramps would connect lower density areas. However, it’s obvious that there’s very little right-of-way available for the missing ramps, and it might be hard for the southeast quadrant ramps to compete with Barham and Forest Lawn, which make a relatively uncongested shortcut serving these movements.

Lastly, looking at the local street ramps, things are actually in pretty good shape. The 170 has a half-diamond to the north, and the 101 has a half diamond to the west. The 134 has a half diamond to the east, though there’s a little friction between the Vineland on-ramp and Cahuenga off-ramp going east. One notable gap is that there’s no on-ramp to the Ventura Freeway west between Pass Ave and Tujunga Ave or Moorpark St, almost 2 miles, so that might be something to try to fix. Going south on the 101, the Vineland Ave off-ramp is uncomfortably close to the 101/170 merge, something we looked at fixing in a post that feels like it was written century ago.

Now, to look at the deficiencies of the interchange, it’s helpful to look at a stylized diagram showing the number of lanes and traffic volumes. Note that the ramps are drawn as simply as possible, ignoring loops and bridges, to make things easier to look at.

(Note: traffic and ramp volumes from Caltrans. Asterisk indicates volumes I increased by 10,000 to get consistent results.)

It’s readily apparent that the central deficiency of the Hollywood Split is that there are only 2 through lanes on the Ventura Freeway (the 134 west to the 101 north and the 101 south to the 134 east). The traffic volumes are more or less evenly split between the 134 and the 101: 68,000 from the 101 south to the 134 east and 62,700 remaining on the 101 south; 63,000 from the 134 west to the 101 north and 64,400 continuing from the 101 north. In order to handle their traffic volumes, these 2-lane ramps would have to flow full for 16 hours a day. Meanwhile, the ramp volumes between the 134 and the 170 are about half of what the movements are in the other directions.

For the purposes of this post, let’s do an updated stylized diagram showing a simple solution for this bottleneck, taking the easiest approach. Let’s bump up the ramps between the 101 and the 134 to three lanes each way. Going west on the 134, that means we just get rid of the lane drop and extend the third lane through the interchange, which would be a basic bridge widening project. This would leave us with 6 lanes going north on the 101 instead of 5 lanes; the sixth lane could be dropped at the next off-ramp, Laurel Canyon Blvd.

Coming the other direction, let’s pick up the southbound onramp from Laurel Canyon Blvd to the 101 south as a sixth lane. We can then split and have 3 lanes go to the 101 south and 3 lanes to the 134 east. We eliminate the 134 east offramp to Riverside Drive, which has relatively low volume, and let that traffic be picked up by the Tujunga Ave and Cahuenga off-ramps. That clears space for the bridge widening for the third lane to the 134 east. With 2 lanes merging in from the 170 south, we have 5 lanes on the 134 east. Rather than drop the right lane and add the HOV lane on the left, let’s just turn the left lane into a carpool lane and force ramp traffic from the 170 over, since it has a lower volume anyway.

Note that we also cleaned up the 101 north to the 170 north transition, making it 3 lanes instead of 4 lanes and eliminating the need for a lane drop on the ramp from the 134 west to the 170 north. In this instance I left the right-side lane drop and added the HOV lane on the left, but maybe the opposite approach would work.

In a future post, I’ll lay this out on an aerial, and take a deeper look at some of the other possibilities for improvements discussed above.

The 101 – Four-Level to Hollywood Split

‘Bout time for a freeway post, no? Prerequisite: principles for urban freeway improvements.

When it opened in 1954, the 101 was a revolution in freeway engineering, incorporating many lessons engineers had learned on earlier efforts. Gone were the tight corners of the 110, and interchanges now had acceleration/deceleration lanes. Breakdown lanes also appeared.

However, the 101 also features the typical shortcoming of 50s-era freeways: interchanges are spaced too close together. Maybe engineers expected lower speeds or smaller volumes, or maybe they just didn’t understand the impact of weaving. Either way, with distant rumblings about the need to widen the 101 – an expensive and disruptive endeavor for sure – it’s time to offer an alternative that helps improves traffic and coincidentally improves the city too. (Or, look at the other way around if you want.)

One good aspect of 1950s freeway engineering is that it usually didn’t blow enormous holes in the street grid to shave a few seconds off motorist delay at offramps and onramps. Instead, ramps are cleverly feathered into the street grid. Consider a typical interchange on the 101 (left) compared to the 105 (right).

So the biggest thing to fix on the 101 is interchange spacing. As a general rule, urban freeway interchanges should be spaced like rapid transit stops: about every mile. Ramps spaced less than a mile apart are counterproductive unless you go to the expense of braiding them, which costs a lot of money and disrupts the city – the opposite of what we want to do here. Don’t take my word for it, ask the folks who wrote the book on freeways. A quick look at the 101 shows that they apparently stuffed in as many ramps as they possibly could, regardless of whether the local street warranted it.

First step, figure out the interchanges. We’ll revisit the design of each in more detail later. Courtesy of our friends at Caltrans, here are ramp volumes for the 101. I used all 2006 data, because this was the most complete set. Numbers marked with a star are 2007 data. The changes since 2006-2007 have been trivial, and reflect a time of very high unemployment anyway. I’ve arranged the data so that complimentary moves are next to each other (e.g. northbound off and southbound on).

Shooting for an interchange every mile, and trying to can the low volume ramps first, here’s my rough layout. Mileposts start from the freeway center of the universe in East LA.

• Four-Level Interchange (MP 3.1)
• Alvarado (MP 4.4)
• Silver Lake (MP 5.3, NB off & SB on only)
• Vermont (MP 5.9)
• Santa Monica/Western (MP 7.3)
• Hollywood (MP 8.0)
• Franklin/Vine (MP 8.6, NB on & SF off only)
• Cahuenga (MP 9.0, SB off & SB on only)
• Highland (MP 9.5)
• Barham/Universal Studios (MP 11.1)
• Campo de Cahuenga (MP 12.1)
• Hollywood Split (MP 13.0)

Ten miles, eleven interchanges.

Note: in all the graphics, green is freeway replaced with undeveloped land. Orange represents land to be developed with new buildings.

Four-Level Interchange

I’m still leaving this one alone for a future post. For now, let’s say that obviously, we’re going to have an interchange with the 110.

Alvarado St

The ramps to/from Echo Park Av (northbound) and Union Av (southbound) are too close to both the 110 ramps and the Alvarado ramps, and they dump freeway traffic onto local streets. The NB off/SB on pair has higher volume than Alvarado, but that may be due to people using those ramps to avoid traffic on the 101 as soon (or for as long) as possible. No one using those ramps would have to go more than 0.7 miles out of their way to get to Alvarado.

Therefore, the Echo Park and Union ramps should be eliminated. The street grid would be reconnected and some property would be redeveloped. No changes are needed at Alvarado, which is a tight diamond.

Silver Lake Blvd

The ramps to/from Rampart Blvd and Benton Way are too close to both the Alvarado ramps and the Silver Lake ramps, and they too dump freeway traffic onto local streets. Closing these low volume ramps would be only a minor inconvenience to those drivers, who would have to travel a maximum of 0.6 miles to get to Alvarado. These ramps should be eliminated.

Meanwhile, the Silver Lake ramps are heavily directionally biased – that is, volumes to and from the south are much higher than volumes to and from the north. (See the ramp volume table; NB off/SB on are much larger than SB off/NB on.) The SB off and NB on ramps are also very close to the Vermont ramps, making for a punishing weave section on the 101. While it’s usually bad practice to not offer all ramp movements at every interchange, in this case an exception is warranted. The SB off and NB on ramps at Silver Lake should be eliminated. No one would have to drive more than about a mile out of their way due to this change.

Again, this would allow the street grid to be reconnected and some property to be redeveloped. No changes are needed at Silver Lake, which is a tight diamond.

Vermont Av

Vermont has by far the highest volume NB off/SB on ramp pair, and the SB off/NB on ramp pair volume is large as well. This interchange is definitely staying.

That creates an interesting question regarding the ramps at Melrose and Normandie. The SB off/NB on ramp pair volume isn’t that bad, but the NB off/SB on pair is high – in fact, the second highest such pair in the corridor. Eliminating those ramps is a tall order, but if they’re not eliminated, they probably need to be braided – the opposite of what we’re trying to accomplish here.

As luck would have it, an accident of history created an opportunity to solve this problem. The median of the 101 is very wide, up to 160’, between Virgil and Melrose. Students of LA freeway history will recall that this is because it was planned to be the location of a freeway interchange between the 101 and the 2, which was to be extended from Echo Park west to Beverly Hills and Santa Monica.

That freeway is never getting built, and the wide median is currently occupied by a self-storage facility. Time to put it to better use.

Between Virgil and Vermont, the southbound side of the 101 would be shifted north. There’s already an empty bay in the middle of the Vermont Av bridge that was reserved for the 2 freeway, so there’s no need to do any work on it. From Vermont to Melrose, both sides of the 101 would be shifted towards the middle, eliminating the wide median. New frontage roads would be constructed from Vermont to Melrose, accommodating the traffic currently using the NB off/SB on pair at Melrose/Normandie.

Finally, the Vermont ramps would be reconfigured to square up the intersections, eliminate traffic lights, and free up land for development. In particular, note the relocation of the SB onramp to line up with Rosewood Av and the new frontage road. This allows Oakwood St to be reconnected and for new development on the north side of Oakwood to screen the freeway.

Santa Monica Blvd/Western Av and Hollywood Blvd

Things are a little bit simpler at Santa Monica, Western, and Hollywood. There’s no need to modify those interchanges. The partial interchange at Sunset/Wilton has high volumes for the NB off/SB on pair, but it’s just too close to the Santa Monica/Western ramps. I’d expect most of that traffic to shift to the Hollywood interchange, which currently has smaller volumes. The SB offramp to Sunset isn’t a huge issue because it’s braided, but its volume is pretty low. That ramp and the SB onramp from Hollywood would be modified into a frontage road and onramp, reconnecting a north-south street in the adjoining neighborhood.

The changes on the southbound side aren’t that big, but eliminating the loop on the NB offramp frees up a lot of land for development and is a huge improvement to the pedestrian environment at Sunset and Wilton.

Franklin/Vine and Cahuenga

The ramps to/from Gower St and Argyle Av are all low volume ramps. They can be eliminated without much issue. The SB offramps to Cahuenga and Franklin/Vine are both high volume ramps, as is the NB onramp from Franklin/Argyle, so they remain. The SB onramp from Cahuenga should remain just because there needs to be a SB onramp somewhere in the area. The NB offramp to Cahuenga should be eliminated, since it is a low volume ramp and creates a murderous weave with the high volume NB onramp from Franklin/Argyle.

Another option would be to replace the braided SB ramps, on from Cahuenga and off to Franklin/Vine, with a frontage road and SB onramp. This would eliminate a couple bridges over city streets, and free up land on the north side of Franklin for development.

Highland

The SB off/NB on ramp pair at Highland is the highest volume ramp pair on the whole corridor, and it’s in a very logical and undisruptive location. That pair is definitely staying. The NB offramp to Highland needs to stay, just to have a ramp in the area, since the Gower and Cahuenga offramps would be eliminated. It’s closer than ideal to the Franklin/Argyle onramp, but so it goes.

The SB onramp from Highland should remain but be closed except when events are ending at the Hollywood Bowl. It’s much too close to the Cahuenga offramp for everyday operations, but it makes sense to keep it for Hollywood Bowl events so that the large bursts of traffic from those events don’t have to go through city streets to get to the freeway.

Barham

The NB off/SB on pair at Barham has fairly high volumes. The NB on ramp at Cahuenga near Pilgrimage Bridge also has high volumes and should remain. The NB offramp to Universal Studios is lower volume, but can remain because it’s not taking up useful real estate or causing any major weave problems. The NB onramp at Universal Studios should also remain.

For reasons unknown to me, the original NB off/SB on pair at Barham was abandoned long ago – all the way back in 1957, according to California Highways. If it can be reactivated, the original NB offramp would increase weaving distance between the Cahuenga onramp and the Barham offramp. However, that might encourage drivers entering northbound at Highland to try to cut across to Barham, which is a major weave and therefore undesirable. Instead, perhaps the Cahuenga onramp to northbound could be relocated south to increase the weaving distance between it and Barham.

Campo de Cahuenga

The Lankershim NB off/SB on ramp pair has larger volumes than Campo de Cahuenga, but it’s too close to the Barham ramps. In addition, eliminating the ramps at Lankershim would improve the pedestrian environment. Pedestrian volumes should be lower on Campo de Cahuenga because there’s nothing there. A SB offramp should be constructed at Campo de Cahuenga, and all movements provided for the NB ramps. The Campo de Cahuenga interchange would replace both the Lankershim interchange and the Vineland interchange, which is too close to the Hollywood Split.

This frees up land for redevelopment on Vineland where the SB loop ramps would be eliminated.

Hollywood Split

The Hollywood Split, with its missing ramps and left-hand exits and entrances, is a project unto itself. I’m going to leave it alone for the time being.

Implementation Timeline

Some of these improvements require building new ramps, which would require more traffic studies and engineering design than easier locations where ramps would just be eliminated. There’s no reason to hold up the easy projects to wait for the more complicated ones to be ready for construction; the easy ones could be completed in less than a year. A few improvements could be accomplished in the midterm, e.g. closing braided ramps with bridges that would need to be demolished. I’d break things down as follows.

Short-term improvements (<1 year):

• Close Echo Park Av & Union Av ramps
• Close Rampard Blvd & Benton Way ramps
• Close Silver Lake Blvd SB off/NB on ramp pair
• Close Normandie Av/Melrose Blvd SB off/NB on ramp pair
• Close Sunset Blvd/Wilton Pl NB off/SB on ramp pair
• Close Gower St/Argyle Av NB off/SB on ramp pair
• Close Cahuenga Blvd NB offramp
• Close Highland Av SB onramp
• Close Vineland Av NB offramp

Mid-term improvements (1-3 years):

• Close and demolish Sunset Blvd SB offramp
• Close and demolish Gower St SB offramp

Long-term improvements (3+ years):

• Close Normandie Av/Melrose Blvd NB off/SB on ramp pair, realign the 101 mainline lanes, and build frontage roads between Vermont Av & Melrose Blvd
• Close and demolish Franklin Av/Vine St SB offramp, construct SB frontage road between Cahuenga Blvd & Franklin Av/Vine St, and reconstruct Cahuenga Blvd SB onramp
• Complete tight diamond interchange at Campo de Cahuenga, close Vineland  St SB off/SB on ramps, close Lankershim Blvd ramps

Staging the implementation allows low-cost improvements to be constructed first. In fact, almost no upfront expenditure would be necessary for the short-term improvements if the land was sold for development, since the developers would assume the cost of removing the existing ramps. This would create some immediate benefits while long-term improvements were studied in more detail.

Conclusion

I know a lot of people really, really don’t like urban freeways. But just saying “tear them down” is a throwaway response that ignores the related issues like land use controls and the role of transportation in cities and economies. It also misses out on opportunities to improve the city that can be made quickly and low cost. The 101, as LA’s first real freeway, is a great place to start, and a successful project here could lead to more short-term improvements across the city.

How Many Parks Does a Civic Center Need?

In previous posts, I laid out some reasons for focusing some attention on the area between 2^nd St and Union Station, and presented an option for improving the 101 in a way that would help restore the urban fabric between downtown and Chinatown. I was originally going to do two more posts, one on land use and one on parks, but they’re so connected that it makes sense to address them at the same time.

Concerning land use, by far the biggest problem in this area is the monolithic area of government buildings, and the accompanying parking uses. In the image below, based on the city’s excellent ZIMAS service, land zoned for public facilities (PF, i.e. government buildings, freeways, schools, fire stations, and so on) is colored blue-green. Other uses per the generalized zoning legend.

The heavy concentration of a particular type of employment, while it creates agglomeration effects, results in inefficient use of infrastructure and land. Infrastructure use is heavy during peak travel periods, and businesses are crowded during  workweek lunch times, but the area is practically a ghost town at other times – try hanging out on Temple on a Saturday night, for example. In fact, the blue-green area pretty much corresponds to the district in question.

This is an important thing to keep in mind when it comes to the parks in this area, because the biggest determinant of a park’s success or failure is everything around it. The parks are shown in dark green in the ZIMAS image above.

Grand Park

As one can see, Grand Park is entirely surrounded by government buildings. Some hope that it will become “LA’s Central Park”. Personally, I think trying to make something “our city’s [insert landmark from another city]” is a bad idea, because it sets us up to try to imitate the features of another city and ignore local context. If Grand Park becomes truly grand, there will be no need to promote it by invoking the image of another city. To their credit, the people running the park have done well at programming events and drawing interest in the park.

Their job would be much easier if the land uses surrounding the park contributed a steady stream of passers-by, people for whom the park was a pleasant way between destinations, not a destination unto itself. This is pretty much straight out of Jane Jacobs writing about Rittenhouse Square in Philadelphia – and wouldn’t you know it, Rittenhouse Square’s 8 acres are not a bad comparison for Grand Park’s 12 acres, much better than Central Park’s 840 acre sprawl.

This means that over time, we need to encourage a greater mix of land uses around the park. There are three blocks between 2^nd and 1^st, from Grand to Broadway that are currently pretty empty. One is a vacant lot that is slated to become a new courthouse, one is a mishmash of parking lots, and one is a steel-frame parking garage that looks like it had no business surviving both Sylmar and Northridge. The first is zoned PF, the other two commercial. After Regional Connector is complete, there will be subway stops at 2^nd/Hope and 2^nd/Broadway, in addition to the existing Civic Center stop at 1^st/Hill.

This is going to create market pressure to redevelop the lots. The parking lots should be upzoned to allow residential, commercial, and retail, with no parking minimums. LA Curbed reports that the GSA is hoping to find a developer to build a new office building next to the new courthouse. Realistically, the downtown office market is already flooded with vacant space. Why not allow residential, for which there is a big demand downtown, to be built here as well? This, along with other proposed developments in the area, will help pull the downtown building boom towards Grand Park.

The government buildings surrounding Grand Park should not be doomed for no reason other than trying to satisfy these urban design goals. Over time, agencies will likely decide to build new, modern facilities and at that time the parcels will become available for reuse or redevelopment. For example, when the new courthouse at 1^st/Broadway is complete, the existing courthouse on Temple between Spring and Broadway can be redeveloped. Conveniently, LA Downtown News has a good look at this issue today.

Graffiti Pit

There’s currently one vacant parcel fronting Grand Park – the shattered remains of a state government building that was terminally wounded by the Sylmar earthquake, colloquially known as the graffiti pit. For reasons I cannot comprehend, the powers that be have decided that solution for this lot is More Open Space – this, despite the fact that the lot already borders Grand Park and City Hall Park. The last thing we need here is more green space.

Before you jump on me, I would implore you to think about how parks work. If that’s not enough, reread the parks chapter of Jane Jacobs. In every article I’ve linked to above, parks are “venerated in an amazingly uncritical fashion”, as she put it. Practically no attention is paid to the land uses around the park that will actually determine if the park succeeds.

A parcel that is bordered by two parks, LA City Hall, the LA County Law Library, and the LA Times should not be a park. It would seem to be a strange use of limited public funds to build yet more open space here. Instead, why not demo the graffiti pit and mitigate any environmental hazards, and then auction off the lot (or lots) to the highest bidders, as I suggested in my post on the 101 in the area? Given current market conditions, residential is probably the most viable use, though this lot is a little bit further from the active areas of downtown and Little Tokyo, which would reduce the desirability.

Unfortunately, we may too far down the open space path to change plans now. Because the virtue of open space is accepted as self-evident, people tend to look askance when you say that a park is a bad idea, and once the park is built, it is very difficult to go back. Nevertheless, I’m still going to try. We really don’t need another park here.

Park 101

To the north of Grand Park, Temple is lined with government buildings on both sides, along with the Cathedral of Our Lady of the Angels. To the west of Figueroa, GH Palmer is building one of its Italian-series buildings, the Da Vinci. North of Temple is the 101 freeway trench, about which I’ve previously written in the context of rationalizing the ramps and improving the street grid. Now let’s look at the Park 101 proposal, which in addition to reconfiguring the ramps would build a deck over the freeway trench with new parks.

Obviously, I prefer my ramp configuration. I’m not sure exactly what Park 101 is proposing, since the “Alternative A” shown in the phasing video looks different than the “Preferred Concept” in the study. But any concept is going to require further study anyway, and the most important thing is to get the ball rolling on a rationalization of the ramps that includes getting rid of the loop ramps that chew up an entire city block. That sets the stage for some selling some property that can help pay for improvements. Park 101 overplans the type of development for my liking; as I’ve said before, we should let the market decide the best use.

Principles for Freeway Cap Parks

To my surprise, the Park 101 Study makes only passing reference to Boston, in the context of increasing property values from the Big Dig. I lived in Boston during the opening of the parks that replaced the 93 freeway elevated structure after the Big Dig tunnels were complete, and there are many lessons to learn about linear parks above freeways from that project:

• The park has to end somewhere, and that location is likely to be unpleasant because it is going to be subject to freeway noise and fumes. No one really wants to hang out at Portal Park. This suggests that the ends of the park should terminate at a building, not a freeway portal. Clearly, in the case of Portal Park, there’s an extenuating circumstance – the desire to provide a view of the bridge – but that’s not the case with the 101.
• Don’t overplan the land uses. It is now almost ten years since the 93 freeway elevated structure was demolished, and precisely one of the designated parcels has been developed – a mixed use block between Causeway and North Washington. On all the remaining parcels, viable development plans have been repeatedly rejected, while the preferred plans have proven untenable.
• Don’t hold the park corridor sacred. In Boston, fanatical NIMBYism has resulted in demands that new development not even cast shadows on the park, which makes it practically impossible to capitalize on the increased land values on the corridor.
• The development is just as important as the open space. The parts of the Central Artery corridor that work well – the North End Parks, the fountain by the aquarium – have strong generators of interest on both sides. The weaker parts – from High St to Congress St – have weak generators on the east side (because there is only one block to a wide expanse of water) and single-use generators on the west side (offices). When the Big Dig started in the 80s, the environmental reviewers arbitrarily decided that 75% of the corridor should be parks because, well, because MOAR OPEN SPACE. Other architects and planners submitted proposals that the corridor should become more like a series of Copley Squares, bounded by development on all sides. In retrospect, these proposals would have made the parks better.

Now, there’s actually another facility in Boston that’s just as instructive: the Massachusetts Turnpike between South Station and Kenmore Square. Like the 101, the Mass Pike is trenched just below street level  along this corridor, and the city would like to cap the freeway with development and parks. Unfortunately, since the construction of Copley Place in 1983, no progress has been made. The Fenway Center might start construction next year, but don’t hold your breath – the Columbus Center actually started construction in 2008, but then withered. A proposed overbuild at South Station seems moribund as well.

The take away here is that air rights have negative value relative to regular vacant lots, due to the need for unusual structural designs and restricted work hours. If there are benefits to the city at large, this may be a rare case where I would make an exception about giving subsidies to developers.

We should also realize that for cap parks design is restricted by structure depth. This restricts the types of landscaping and park features that can be installed. Also, since you’re on a bridge, at some point you’ll probably have to rip everything out to rebuild the structure.

Finally, if you cap a freeway over a long enough distance, it’s functionally a tunnel, which means you need to provide expensive things like tunnel ventilation (far more costly for freeways than for transit), emergency egress points, fire standpipes, and so on. Therefore, to be cost effective, we should keep the freeway cap sections short enough that they don’t trigger tunnel reviews.

Note that as is often the case with urban design goals, sometimes there is synergy between goals, and sometimes goals are in competition. There are trade-offs to be made. For example, the desire to terminate the park with a building is in conflict with the fact that air rights have negative value. The desire to connect the city to the greatest extent possible is in conflict with trying to keep the cap sections short. These trade-offs can be a question of how much money we want to spend. It’s easy to say we should have more freeway caps, but recognize that public funds are not unlimited. Every dollar we spend here is a dollar we can’t spend on improvements somewhere else.

Alameda to Broadway

The need for a better connection between Union Station and downtown is the most acute between Alameda and Broadway, and it’s no coincidence that in this stretch Park 101 makes the most sense. Logically, this is also proposed to be the first phase of the project.

With the principles outlined above in mind, I think we can get the benefits of Park 101 without capping as much of the freeway or spending as much money. I agree with the Park 101 study that the logical first piece of the cap is the block between Los Angeles and Main. That suggests that the blocks to the north and south should be covered with air rights developments. In the interest of reducing tunnel ventilation and egress costs, I would consider the leaving the center portion of the block open to the air, especially on the large block between Alameda and Los Angeles where the freeway is abutted by onramps that make overbuild difficult anyway.

Note that while public subsidies might be required to induce air rights development on these parcels, the public contribution would hopefully be less than what would be needed to build the cap park. The air rights development would also be beneficial because it would create tax-paying properties and generate more users for the cap parks. More users close to the parks means more successful parks.

With the block between Main and Spring used for air rights development, it’s logical for the next block to the north to be another cap park, between Spring and Broadway. I’ve updated the crappy MS Paint graphic from my post on the 101 to show this concept. Click to enlarge.

Broadway to Grand

As you can see from the graphic, I didn’t do much to cap the freeway between Broadway and Grand, because the value of doing so is lower in this area. Between Alameda and Broadway, the 101 is spanned by 5 bridges with spacing between 350 and 550 feet. It’s over 1,200 feet from Broadway to Grand, with no side streets. In addition, this area is bounded by the Cathedral of Our Lady of the Angels and the Cortines School, both of which have logically turned their backs to the freeway.

With no side streets and little prospect of redevelopment on the abutting properties, there will be very few generators of park users for this quarter-mile stretch. Therefore, in this area I think it makes sense to terminate the park with an air rights building between Broadway and Hill. This building could provide a way to bridge the grade difference between Broadway and Hill to help integrate Hill into the street network.

If anything is to be done at Grand, I’d favor an air rights building on both sides of the street, which would reconnect the street façade from Temple to Chavez.

Alameda to LA River

In this area, I disagree with the Park 101 approach. This area is industrial, and there are overhead transportation facilities (the Gold Line and the El Monte Busway). If the Union Station run through tracks and the CAHSR project are constructed, there will be even more overhead transportation facilities. Those facilities are noisy, and the railroad tracks have sharp curves, which makes them noisier. It’s not going to be very pleasant to hang out underneath these bridges, and not many people are going to want to live or work in expensive high-rises adjacent to them.

In this area, Park 101 would also require taking a large amount of property by eminent domain. Progressives seem to have this weird MO where they worry about the loss of industrial and manufacturing jobs in cities in theory, but promote plans that eliminate those jobs in practice (see the Cornfield for example). Now, maybe industry won’t be the best use of this land when Regional Connector is complete and Little Tokyo and the Arts District keep growing, but that can be addressed by upzoning and letting property owners decide what to do. That puts money into city coffers rather than draining them.

For now, this area is a functioning industrial zone, so I think we should let it be. I put in one air rights development on the east side of Alameda to help reconnect the street façade with Union Station.

Main to Spring Option

As another option, I would consider making the block between Main and Spring a park instead of air rights development. This would create a three-block long park between Aliso and Arcadia from Los Angeles to Broadway. With development on Aliso and Arcadia, and air rights development to terminate the view at Broadway and Los Angeles, this would work pretty well too. It would cost a little more in terms of structure and ventilation. Click to enlarge.

Freeway Widening

The Park 101 Study assumes that the 101 would be widened by at least one lane. The conceptual section on page 45 appears to show a clear span of about 100’ on the 101 north and about 85’ on the 101 south. In contrast, most of what I’ve shown assumes a clear span of about 65’-80’. This is a big difference, because the costs do not scale linearly. Long spans require deeper structures and are considerably more costly; this is the reason that air rights have negative relative value.

District 7 may not want to hear it, but the 101 is wide enough here. Much of the congestion northbound is spilling back from the merge at the Four-Level, which means unless they’re planning to build a fifth lane all the way to the Hollywood Split, widening here won’t do too much. Southbound, the congestion builds back from the East LA Interchange and is related to merging, weaving, and capacity issues on the 60 east and the 5 south. Again, those issues are not going away anytime soon. Personally, I wouldn’t feel too bad about locking the 101 into its current number of through lanes here, and this isn’t even an anti-freeway blog.

Summary

Both of these options create considerably less open space than Park 101, but I think the open space created would be more valuable. These options would also allow more development, which generates more revenue for the city. I don’t think the area is at a loss for open space; Grand Park is close and the Cornfield and Elysian Park aren’t too far to the north. I think these options would be more affordable, which means they could be implemented sooner and would have less of an impact on our ability to improve parks elsewhere in the city.

No one should interpret this as an attack on the Park 101 concept; I’m sure a lot of work has gone into the project. The point here is to realize that there are many options beyond just capping the freeway with parks, and we should look at a wide range of alternatives and realize the trade-offs between them.

From 2^nd to Union

That about wraps it up for my look at this area for the time being. If I could emphasize one point above all else, it would be the thing that makes a park great is the city around it. Planning in this area needs to start with that fact as the central premise.

The 101 – San Bernardino Split to the Four-Level

In a previous post, I provided some setup for studying the area between 2^nd and Union Station. In this post, let’s look at the 101. In another post, I set some ground rules for improving urban freeways, the main gist being that freeway projects and urban improvement are not necessarily mutually exclusive goals. So let’s see those principles in use on the 101.

There’s a lot of attention focused on the area between Union Station and 2^nd St lately, and why not? With the development boom downtown, the popularity of Little Tokyo, Grand Park, and transit improvements all over the place, there’s a lot to be excited about. Slicing through the area, first west by north, then northwest, is the iconic 101 freeway – symbol of LA freeways, of LA traffic, of LA growth and sprawl, of LA in general. The Four-Level Interchange even appears on book covers and postcards.

The 101 is the prototypical 1950s freeway, showing the lessons that highway engineers learned from their first attempts. The 101 wasn’t even in the same class as freeways like the 110 north of downtown, which was (and is) a disaster of sharp curves and contorted 5 mph ramps. However, the 101 shows typical 1950s flaws, the biggest being interchanges that are too close together. Engineers eventually figured that out too – check out the 210 between the 57 and the 15 for example.

The 101 between the San Bernardino Split and the Four-Level (i.e. from the 10 to the 110) is one of the most congested freeways in the city. I’m writing this at about 10:30pm and I just opened Google Maps and – yep – it’s yellow. It’s also a considerable barrier between Union Station and downtown. So it’s the perfect place to demonstrate these principles. Let’s run through an option for making things better here, from south to north.

Note: you might want to open up Google Earth or another tab to look at how the images below compare to today. The biggest benefits, from an urban form perspective, are on the north side of the freeway between Alameda and Broadway, on Grand on the north side of the freeway, and at Temple and Hope.

San Bernardino Split

This interchange has undergone modifications in the past. There used to be a ramp from the 10 west to the 101 south, which made redundant when the 5 was constructed, because the ramp from the 10 west to the 5 south serves the same movement. This ramp was removed when the El Monte Busway was built. However, the opposite move, from the 101 north to the 10 east, still has a ramp, and it’s just as redundant.

This ramp should be repurposed into an exit from the 101 north to Chavez and an entrance from Chavez to the 10 east. The utility of this interchange will become apparent shortly. Concurrently, the slip ramps to and from Kearney St should be eliminated, removing freeway traffic from local streets in Boyle Heights.  These ramps would also give traffic coming east on Chavez an entrance to the 10 east without going through Boyle Heights.

Mission Interchange

The ramp from the 10 west, to the 10 east, and to the 101 south are relatively benign, so they should be left alone. The ramps from the 101 south to Mission and from Mission to the 101 north are theoretically too close to interchanges to the north. However, they should also be retained, since they provide access to and from industry on the east bank of the river without sending traffic through Boyle Heights. (Issues on the 101 between the 10 and the East LA Interchange will be addressed in a separate post.) Considering the congestion on the 101 north here, you’d be a fool to get on at Mission anyway, and I don’t think many people do so.

Vignes/Garey Interchange

I like to call this style of interchange a “kiss interchange” since the ramp termini look like puckered lips in plan view, making it look like the freeway is kissing the other road. Since they’re cheap to build, these are plunked down all over the place on 50s-era freeways. The ramps at Vignes and Garey are all much too close to the preceding and following interchanges, and they’re redundant anyway, so they should all go. Northbound traffic would get off at the new Chavez ramp I mentioned above or at Alameda; southbound traffic would get off at Los Angeles. Traffic entering northbound should enter further north; traffic entering southbound should enter at Los Angeles or from Mission.

Alameda/Los Angeles Interchange

The ramp from the 101 north to Alameda should be retained and become one of the primary exits to the downtown area. It takes up little ROW, provides access to Alameda and Union Station, and provides access to other north-south arterials via Arcadia.

The ramp from the 101 south to Los Angeles should be retained and reconfigured to also provide access to Aliso eastbound. Access to Los Angeles northbound is not critical because there is a left from Aliso to Alameda northbound. This allows this ramp to serve the functions of the eliminated Garey St offramp.

The ramp from Los Angeles to the 101 south should be retained and lefts should be permitted from Los Angeles southbound onto this ramp. This ramp becomes one of the main southbound entrance points and assumes the functions of the eliminated Garey St onramp.

The ramp from Los Angeles and Alameda to the 101 north takes up an entire city block, directly across from Union Station. This ramp should be configured as a slip ramp from the intersection of Aliso and Alameda onto the 101 north.

Spring/Broadway Interchange

The ramp from the 101 south to Broadway is way too close to the onramp from the Four-Level. It should be eliminated and replaced by an extension of Aliso north to Grand and improvements further north. Due to the crazy grade changes in this area, it’s not possible to have the extension of Aliso intersect Hill – it’s too high up.

The ramps from the 101 north to Spring and from Broadway to the 101 north take up an entire city block, have terrible geometry, and are too close to adjacent interchanges. These ramps? Gone. Arcadia should then be extended north to Grand. Again, the grade differences make it impossible for the extension of Arcadia to intersect Hill.

Grand/Hope Interchange

It would be nice to turn the loop ramp from the 101 north to Grand into a slip ramp on the south side of Grand, but the severity of the topography in that area would push the ramp too far south, close to the Alameda onramp. Instead, the ramp should duck under the onramps  and in a slightly larger loop and terminate at Grand where the onramps currently start. The onramps to the 101 north should be moved to the west and square up with the extension of Arcadia. I considered sending the offramp to turn right onto Bunker Hill and come out at the intersection with Chavez, but that would add a ton of traffic turning right from Bunker Hill to Chavez and then Chavez to Grand, so I nixed that. I also thought about sending this ramp to the left under the 101 to come out at the intersection of Hope and Temple, where the ramp from the 101 south currently ends, but I don’t think that grading would work.

The 101 south ramp that currently goes to the intersection of Temple and Hope should be reconfigured to square up with the extension of Aliso, and Hope should be extended to that intersection. The offramp to Temple from the Four-Level ramp that heads to the 101 south should be reconfigured to square up with the intersection of Hope and Temple (taking the place of the current ramp from the 101 south).

Another option would be to get rid of the fork of the onramp from Grand that goes to the Four-Level and just let that traffic use Figueroa to the 110. The offramp to Temple and Hope from the Four-Level ramp could be eliminated too, and replaced by a better configuration of the offramp from the 110 south to Figueroa. However, I decided against this option because the ramp from Figueroa to the 110 north and from the 110 south to Figueroa should probably be eliminated as part of rationalizing the ramps on the 110 (more on that another time).

Four-Level Interchange

I’m a little gunshy about going after the Four-Level. After all, it’s basically where freeway engineering was born – the  first high-speed semi-direct interchange ever. But LA ain’t a museum, just ask the people in Beverly Hills buying $10m teardowns. Nostalgia is for chumps. The Four-Level was fully opened in 1953, before the 10 and the 5 were complete. At that time, it was necessary to provide all the movements. But at this point all four movements to the 101 south and from the 101 north may be redundant.

I started looking at options for eliminating and reconfiguring ramps at the Four-Level, but you know what? Any changes to the Four-Level are only about eliminating short weaving distances and redundant ramps on the 101 and the 110. They’re not about improving the streets downtown for pedestrians or cyclists, and they’re not about reducing ROW footprints and opening up land for redevelopment. Now, maybe it’s worth doing some improvements at the Four-Level, but they’re a separate issue from what I’m trying to get with this series of posts, which is better connections from the Union Station area to downtown. So let’s leave the Four-Level alone for the time being.

Other Options Abound

This is, of course, just one option, and there are plenty of other ways you could configure things. Come up with your own, and let’s get to work on convincing the city and Caltrans to do an analysis.

Now We Have Real Estate to Work With

The land vacated by these ramps should be redeveloped. And instead of doing the normal deal where we have a design competition, give the developer unreasonable subsidies, and end up with vacant lots for years, how ‘bout this: zone the land for any residential or commercial use (and industrial for the piece on Commercial St), no parking minimums, no tax abatements or subsidies, no FAR/height limits, no nothing. We just auction it off to the highest bidder with two conditions: no surface parking, and you gotta build something there within 5 years. We should also break up some of the larger blocks into a few different parcels and auction them off separately. You want to buy the whole block, ok, but you have to win the bid for each piece.  It’ll be a fun experiment.

This project really is an all-around win. It opens up new land for urban development, which unlike any of the proposed parks in the area, actually helps connect Union Station and downtown. It fixes dangerous conditions on the freeway that waste capacity. It makes things better for pedestrians and bikes by getting rid of loop ramps and improving the street grid. And the ROW sale would help fund the project. What’s not to like?

Note: you used to be able to import Google Earth images and topographic data into AutoCAD, which was pretty sweet, because you could draw real engineering stuff and then export it back to Google Earth. As part of Google’s continuing campaign to make its products worse, this feature is no longer available. This leaves several crappy options for trying to share this kind of work:

• Find the best aerial you can get in AutoCAD (often way out of date) and work with that (but then it’s a static picture other people can’t look at in Google Earth).
• Draw with polygons in Google Earth and hope that the geometry isn’t insane.
• Draw it in SketchUp, which is basically like trying to cut down a tree with a jackhammer: it’s not that it’s a bad tool, but it’s clearly not designed for this type of work. I could write an entire post on how bad SketchUp is for civil engineering, if I was looking for exercises in futility.

Therefore, for now, I’ve gone for the fast route with questionable accuracy – drawing Google Earth polygons. I’m going to try to update this using SketchUp to verify the geometry and give others the ability to edit, but I’m not making any promises.

Contact me if you want the Google Earth shape files.

Update

At Kenny Easwaran’s suggestion, here is an image of the whole corridor. Click to enlarge. Again, apologies for the low quality, but Google Earth and MS Paint is the fastest way to get it done.

Going north on the 101, after First St, your exits would be Chavez, Alameda, Grand and the Four-Level. Going south on the 101, after the Four-Level, your exits would be Grand, Los Angeles, and Mission. Your entrances to the 101 north would be Mission, Alameda, and Grand; to the 101 south, Temple/Hope, Los Angeles, and Mission.

Downtown Wanderings

This is a short setup post with some background ideas and information that will be useful for a few posts that I have on my mind.

Jane Jacobs wrote about the forces that cause downtowns to drift, like self-destruction of diversity, and offered some ideas on how city planners could work to stop those forces. Lately, I’m not entirely sure that it’s a bad thing for downtown to wander as economic agglomerations come and go. When downtown shifts, it leaves behind an interest and coherent, and perhaps most importantly, cheap district that will eventually be discovered and put to use in ways no one thought of before. See, for example, the industrial buildings of Soho that became artist spaces, or the SROs and boarded-up hotels of Downtown LA that are turning into fancy lofts.

The original Downtown LA was, of course, the pueblo. By the late 1800s, it migrated south to the area around First and Broadway, though the vestiges of this downtown are basically gone. In the early 1900s, downtown was centered between Main and Hope, from maybe 3^rd to 7^th. This area has been booming recently; old-timers will tell you about people living in tents on the sidewalk on Spring St and long vacant buildings, but now Skid Row has moved east and the empty buildings are being renovated. LA’s first skyscraper boom moved things west, to the “new downtown” between 1^st and 7^th, from the 110 to Grand. Now that area seems a little tired, and all the action has moved south again, from Wilshire to Pico, the 110 to Broadway. But who knows, in 20 years, we could be talking about unforeseen redevelopment and action springing up in what used to be the “new downtown”. Predicting the future is hard!

For the most part, we shouldn’t worry too much about downtown wandering. The goal of public policy is to create a solid framework for the city (transpo, utilities, schools, public safety, recreation, etc.) and let the private sector figure out the rest. Sometimes, though, we need to dig a little deeper and figure out what might be holding back the development of a neighborhood. Right now, we have a lot of transportation money being invested in the area between 2^nd and Union Station, to the north of downtown, but downtown keeps shifting south. Why?

Union Station already has the Red/Purple Lines, the Gold Line, Metrolink, and Amtrak. It’s got a lot of Metro bus routes and LAX Flyaway. Before long, Regional Connector will bring the Blue/Expo Lines in to connect, and drop three new stations along 2^nd at Hope, Broadway, and Central. Metrolink may build through-running tracks, and hopefully before too much longer CAHSR will come to Union Station. Despite the “7^th/Metro Center” moniker (a confusing name that should be replaced with “7^th/Flower” anyway), Union Station is pretty clearly the transportation hub. But downtown keeps shifting south. Why?

The appeal of the area between Wilshire and Pico is pretty obvious. It’s got a good mix of old buildings that can be renovated, new construction, and parking lots that are cheap to redevelop. It’s close to many restaurants, bars, and LA Live, and it’s got a Ralph’s on 9^th, a Target on Figueroa, and a Walgreens and a Rite-Aid on 7^th. It’s pretty close to the Blue/Expo Lines and it’s easier to get to the 10 west and the 110 south. I don’t want to suggest taking anything away from this area; its development should be promoted too.

However, given all the money going into transportation between 2^nd and Union Station, we ought to take a hard look at why development there has been somewhat muted. Focus on the framework or “bones” of the city, and I see three main issues:

• The 101, which creates an unpleasant traffic corridor that separates Union Station from downtown.
• An excessive amount of park space that increases the distance between different land uses.
• Zoning and an associated concentration of government buildings filled with people who have pretty much the same schedules and types of trips, which impedes the formation of a customer base large and diverse enough to support a wide range of business establishments.

I’ll explore each of these in a more detailed post.